“…In particular, Diels‐Alder, that is, [4π + 2π], cycloadditions have received extensive attention, so the focus here is on several examples of less commonly proposed (3 + 2) dipolar cycloadditions (Figure ). Using SMD(water)‐M06‐2X/6‐311++G(d,p)//M06‐2X/6‐31+G(d,p) computations, Tantillo and coworkers predicted that both inter‐ and intramolecular nitrone/alkene cycloadditions proposed for formation of flueggines and virosaines have free energy barriers of approximately 20 kcal/mol . Houk and coworkers, using M06‐2X/def2‐TZVPP//M06‐2X/6‐31+G(d,p) calculations, predicted that a similar intramolecular nitrone/alkene cycloaddition proposed to be involved in lycojaponicumin biosynthesis, again has a barrier of approximately 20 kcal/mol .…”